In 1932, McBain put forward the concept of “molecular sieve”. Molecular sieves are a class of materials with uniform micropores having a pore size that is equivalent to the common molecular size. Molecular sieves are widely used, for example, as high-performance desiccants, selective adsorbents, catalysts, and ion exchangers, etc. However, the chemically synthesized molecular sieves are expensive. The commonly used molecular sieves are crystalline silicates or aluminosilicates, which are Si—O tetrahedrons or Al—O tetrahedrons bonded by oxygen bridges to form a pore system and cavity system of molecular size (usually 0.3 to 2 nm) and having the capability of screening various fluid molecules because the size and shape of the adsorbed molecules are different, and mainly used in automotive, architectural glass, medicine, paint & coatings, packaging and other fields. The working principle of molecular sieves includes adsorption function, where the adsorption of substances by the molecular sieves is physical adsorption (via van der Waals force), because the crystal cavity has a strong polarity and Coulomb field therein, and exhibits a strong adsorption capacity for the polar (such as water) and unsaturated molecules; and screening function, where the molecular sieve has a very uniform pore size distribution, and only the substance having a molecular diameter that is less than the pore diameter can enter the cavity of the molecular sieve. The molecules of different substances are discriminated according to the order of adsorption and the size. Therefore, such materials are vividly called “molecular sieves”.
The salt lakes in the northwestern region of China contain abundant salt mineral resources. These salt mineral resources are very important for daily life, agriculture, industry and military industry. For example, potassium salt is the most important component in the potash fertilizers, a main component of explosives, and an important medium for heat storage by new energy resources; and sodium salt is an essential substance consumed by human in daily life. However, the brine in the salt lakes also contains a large amount of various metal ions and salt compounds. At present, chemical purification is generally an approach to effective use of these salt mineral resources. Such methods are costly and not environmentally friendly. Attempts are also made to extract the metal ions targetedly from the brine in the salt lakes by using an ion sieve. However, this method is less efficient when carried out in an aqueous solution,
Accordingly, it is necessary to provide an environmentally friendly material and/or process for purifying a deteriorated or impurity-containing salt compound, so as to increase the production efficiency, and reduce the production cost.